[clang] [clang][CodeGen] `sret` args should always point to the `alloca` AS, so use that (PR #114062)

[Alex Voicu via cfe-commits]

https://github.com/AlexVlx commented:

> We can't keep waiting for this to get in the release  

I'll merge later today once CI passes.

https://github.com/llvm/llvm-project/pull/114062